英语听力文摘 English Digest 696 氧气有毒么？（在线收听）

Can Oxygen Be Toxic?

In order for us to live we must have oxygen, so how can it be bad for us? Today we explain how oxygen can be toxic.

Toxic? Really?

Unbeknown to most people, too much oxygen can be toxic. After several days of breathing nothing but pure oxygen, you’d begin to experience nausea, dizziness, muscle twitches, and convulsions. You might even die.

Ironically, too much oxygen actually inhibits ventilation and ends up slowing down the delivery of oxygen to your body’s tissues. Another problem is that certain tissues, like the lining of the lungs and the walls of the arteries, are very sensitive to oxygen. The cornea is also very sensitive to oxygen; you may have heard of people who have gone blind because, as newborns, the oxygen levels in their incubators were too high.

Oxygen Molecules

Scientists aren’t really sure why oxygen affects the body this way. Some think it has to do with a special form of the oxygen molecule which bonds with the proteins and membranes in the lining of the lungs, and ends up destroying them. In other words, with too much oxygen around, your insides begin to oxidize.

氧气有毒吗？

为了我们的生存，我们必须有氧气，所以它怎么会对我们有害呢？今天我们来解释氧气是如何有毒的。

有毒是真的

大多数人都不知道，氧气过多会有毒。几天只呼吸纯氧后，你会开始感到恶心、头晕、肌肉抽搐和抽搐。你甚至可能会死。

具有讽刺意味的是，过多的氧气实际上会抑制通气，最终会减缓氧气向身体组织的输送。另一个问题是，某些组织，如肺的内衬和动脉壁，对氧气非常敏感。角膜对氧气也非常敏感；你可能听说过一些人失明，因为作为新生儿，他们的孵化器中的氧气含量过高。

氧分子

科学家们还不清楚为什么氧气会这样影响身体。一些人认为这与一种特殊形式的氧分子有关，这种氧分子与肺部内层的蛋白质和膜结合，最终破坏了它们。换句话说，氧气过多，你的内部开始氧化。